I think if you put him in his crib w/out any remnants of bedtime routine, and not too near bedtime, you should be fine. BABYWISE says it's good to have Baby playtime in the crib. I think tracy does, too, especially for the babies who are afraid of the crib. It's also helpful if you need to put Baby somewhere when he's mobile, and you don't have a playpen handy. My friend did crib playtime w/ her son for the same reason, and he does bedtime fine!
-court